Astronomers believe they have found a second planet outside our solar system that seems to be in the right zone for life - just.

But it would feel like a steam bath - hot, sticky and beyond uncomfortable.

European astronomers announced the discovery along with about 50 other planets outside our solar system at a US conference.

The most exciting of those planets is the second to be confirmed as lying in what astronomers call the habitable zone, or the "Goldilocks zone". That means it is not too hot and not too cold for liquid water to be present. Water is the key to a planet being able to support Earth-like life, scientists say.

Only one of the past discoveries of such Goldilocks planets has held up - found in 2007. And even this new one comes with a warning - the planet would need to have water and be a rocky, solid planet like Earth, not one that is primarily gas like Jupiter.

The new planet is about 3.6 times the mass of Earth. Temperatures there may range from 30C to 50C with plenty of humidity.

"It's going to be really muggy. Just think about the muggiest (Washington) day you can think of," said study author Lisa Kaltenegger, an astronomer with the Max Planck Institute in Germany. "We're not saying it's habitable for you and me."

But other types of life - probably shorter and squatter life - could conceivably take root there, she said. They would probably be closer to the ground than humans because gravity on this larger-than-Earth planet is about 1.4 times what we experience, she said.

For it to be considered liveable by astronomers, at least 60% of it would have to be covered in clouds, said Ms Kaltenegger. Earth has about 50% cloud cover, so 60% seems reasonable, she said.

The new planet, called HD85512b, closely circles a star about 35 light years from Earth in the constellation Vela. Each light year is 5.8 trillion miles. A year there is only 60 days. The only reason it might not be too hot for life is that its sun is about 1,000C cooler than our sun, Ms Kaltenegger said.